A method and apparatus for enhancing the integrity of an implantable
sensor. Voids formed between an outer tubing and a sensor substrate or
spacing element may be back-filled with a curable, implantable material,
minimizing the extent to which unwanted fluids diffuse within the sensor.
An enzyme or protein matrix pellet below the sensor window may be
pre-treated with a reducing agent to enhance its bond stability, and to
reduce undesired swelling that may cause the sensor window to detach or
leak. The bonding between the enzyme pellet and a hydrogel layer may be
reinforced by application of an intervening bonding layer of a protein
material, such as human serum albumin (HSA). The size of the window may
be minimized by minimizing the size of an underlying electrode, providing
reduced flux and lengthening sensor. A coating may be deposited on the
surface of the sensor leads, providing stiffening and lubrication.